The immediate problem is that you have enabled the INTERPOLATE option, which interpolates Perl variables anywhere in the template. That makes the module attempt to replace $( by its value, and destroys the JavaScript syntax

It's a sloppy way of using templates anyway: you should pass all the values you need in the $vars hash, and extract them from there using [% variable %] template directives. The same applies to the EVAL_PERL option, as any complex data manipulation should ordinarily be in the code that calls process. Everything you need to do inside the template is available as a Template directive

Talking of the $vars hash, you should be getting Not a HASH reference errors, because you are passing to process a reference to the string variable $result instead of a hash containing that value. It's unclear how you want that value to be handled, but the only mention of id in your HTML is the id attribute of the <input> element at the bottom of the HTML, so I've put a directive in their to show you how it all works

I have modified your HTML file like this. I couldn't tell what you wanted to do with the value that the CGI code pulls from the user_text parameter, so I put it into a value attribute for the first input field

And here's the resulting output from the CGI code. As you can see, the $("#user_text").keyup call remains intact, and the value from the CGI code—the result element passed in the $vars hash—has been substituted into the value attribute of the text input element